A NAT has been agreed upon by what are currently the two largest houses.
PaulAtreides of the Templar_Order and Chrysander of BlackStar announce the following terms of the treaty:

1. 60 day notification prior to cancelation by either house leader.
2. No support or shelter for an enemy of the other house.
3. Respect of territory: formal request must be made and permission recieved to fly into the terriotory of the other house.
4. a. Resolution of violations: If a member of either house violates the NAT by attacking the other house, the house leaders will confer to resolve the dispute and attempt to make full restitution.
4. b. If the player refuses to respect this NAT and violates it a second time, he shall be an outlaw and shall not enjoy the protection of his former house.
5. Ammendments to this treaty including extensions to wing-houses shall be mutually agreed upon by the house leaders.

As michimike read the new achievement of the negotiation between the two largest houses, he stumbled on point 2, "No support or shelter for an enemy of the other house. "
He questions on what happens if this "enemy" was ally of the other house. In an alliance they would have to shelter... is this NAT more worth than an alliance?

But in an alliance you assure your ally to help him in war, if he asks for help. So if you attack an ally of BlackStar - only in theory - BlackStar would be forced to attack you or at least to defend him or offer him to be sheltered.